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Could COVID-19 cause diabetes? A diabetes expert unpacks the science.

We were recently sent this fascinating article from Prof. Larry A Distiller, the Principal Physician and Executive Chairman of the CDE.

In it, he outlines the ‘bidirectional’ effect of COVID-19 on diabetes. Could COVID-19 cause diabetes? Read on to find out.

could covid-19 cause diabetes?

Early in the COVID-19 pandemic, it became clear that those individuals with diabetes who were infected with COVID-19 had a worse prognosis than the general population. However, it has also been noted that in some cases, COVID-19 infections seem to cause diabetes.

Two recent publications highlight these issues.

Worse outcomes in people with diabetes

A recent meta-analysis of the literature published in the journal Diabetologia has confirmed worse outcomes in people with diabetes. There seems to be many reasons for this. Glycaemic control on admission for COVID-19 infection is one. Those admitted with blood glucose levels above 11 mmol/l had an 8.6 times greater chance of dying than those admitted with glucose levels below 6 mmol/l. In addition, the risk of death was increased in those with comorbidities (the presence of one or more additional medical conditions often co- occurring or co-existing with a primary condition). Underlying cardiovascular disease, increased the risk of dying by 56%, and chronic kidney disease by 93%. Further, male gender, older age and the need for insulin therapy (often linked to long duration of Type 2 diabetes) was also associated with a higher mortality.

In those with Type 1 diabetes, there is a very high incidence of severe diabetes ketoacidosis on admission.

Could COVID-19 cause diabetes?

The other side of the coin is highlighted in a publication in Diabetes, Obesity and Metabolism. This looked at the proportion of newly diagnosed diabetes in people with COVID-19 infection. This is commonly observed, occurring in as many as 14.4% of those admitted to hospital with COVID. Again, a number of factors may be responsible. Undiagnosed Type 2 diabetes is common and may have been present before contracting COVID-19. The severe inflammatory response induced by the virus and the resultant need for corticosteroid treatment may precipitate diabetes in prone individuals. However, there is also evidence to suggest that the virus itself may directly destroy the insulin-producing beta cells of the pancreas.

Globally, we now face two major pandemics – an acute COVID-19 pandemic and a chronic pandemic of diabetes mellitus. Our concern is that they appear to be interrelated in a omplex and synergistic interplay.

Takeaway messages

  • Your prior state of health and health risks greatly influence the severity and outcomes of COVID-19 infection.
  • COVID-19 has chronic health consequences beyond the initial infection.

If you know that you have diabetes and possibly any of its complications, please contact your diabetes care team as soon as possible to ensure that your blood glucose and other risk factors are well-managed.

If you don’t have a regular caregiver for your diabetes, the CDE may be able to assist with a CDE-Accredited health professional near you. Visit

How do I know if I have undiagnosed diabetes?

Symptoms of diabetes are of two types:

  1. Classical, specific: passing large amounts of pale, sweet urine frequently, extreme thirst, weight loss, fatigue
  2. Non-specific: blurred vision, tingling of hands and feet, slow wound healing, fungal infections (esp. genital).

But, most people with diabetes (older adults with Type 2 diabetes or late onset Type 1 diabetes) may not experience any symptoms for many years and may present with potential complications of diabetes at diagnosis.

Two thirds of South Africans are undiagnosed

Thus, two thirds of sub-Saharan Africans with diabetes are undiagnosed and at risk for health- and life-threatening complications of diabetes and COVID-19 infection.

However, people with a high risk for diabetes have one or more of the following risk factors that should prompt a doctor’s visit and laboratory screening for diabetes to enable earlier diagnosis and management:

All adults (any age) who are overweight (body mass index (BMI)> 25 kg/m 2 or > 23 kg/m 2 in Asians), plus one or more additional risk factors:

  • Physical inactivity
  • High blood pressure / hypertension [blood pressure (BP) ≥ 140/90 mmHg] or on treatment for hypertension
  • Close family relative (parent, full sibling or child) with diabetes
  • Serum cholesterol problems
  • Polycystic ovarian syndrome
  • High-risk ethnicity (Asian Indian, Coloured)
  • Cardiovascular disease history
  • Previous gestational diabetes or giving birth to a baby > 4 kg
  • History of any blood glucose abnormality
  • Other conditions associated with insulin resistance (severe obesity [especially around the tummy area] and acanthosis nigricans [dark, velvety patches of skin often appearing in the armpits, groin and neck]).

If you have any of the risks referred to in this article, don’t delay in seeking medical advice to proactively identify and manage any risks to your health in these challenging times. Never before has the ancient adage “prevention is better than cure” been more apt.


  • Sathish T, Kapoor N, Cao Y, Tapp RJ, Zimmet, P. (2021). Proportion of newly diagnosed diabetes in COVID-19 patients: a systematic review and meta-analysis. Diabetes Obes Metab, 23, pp. 870-874. Available from: (Accessed 11 May 2021).
  • Schlesinger S, Neuenschwander M, Lang A, et al. (2021) Risk phenotypes of diabetes and association with COVID-19 severity and death: a living systematic review and meta-analysis. Diabetologia. 28 April 2021. Available from: (Accessed 11 May 2021).
  • The Society for Endocrinology, Metabolism and Diabetes of South Africa Type 2 Diabetes Guidelines Expert Committee. “Chapter 3: Screening and diagnosis of type 2 diabetes and intermediate hyperglycaemia” in 2017 SEMDSA Guideline for the Management of Type 2 Diabetes. JEMDSA 2017; 21(1)(Supplement 1): S1-S196.
  • Vas P, Hopkins D, Feher M, Rubino F, B Whyte M. Diabetes, obesity and COVID-19: A complex interplay. Diabetes Obes Metab. 2020 Oct;22(10):1892-1896. Available from: (Accessed 11 May 2021).

What to read next?

COVID-19 and diabetes in South Africa: All the latest, expert advice. The one article you should read about COVID-19 and diabetes.

Should diabetics get the COVID-19 vaccine? We ask a South African expert.

Our COVID-19 and diabetes library of information.

Photo by CDC on Unsplash

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Sweet Life is a registered NPO/PBO (220-984) with a single goal: to improve diabetes in South Africa. We are funded by sponsorships and donations from aligned companies and organisations who believe in our work. We only share information that we believe benefits our community. While some of this information is linked to specific brands, it is not an official endorsement of that brand. We believe in empowering people with diabetes to make the best decisions they can, to live a healthy, happy life with diabetes.